Drax, the UK’s largest power station is situated in North Yorkshire, dwarfing the neighbouring village it is named after. It is situated on the River Ouse between Selby and Goole and has a generating capacity of 3,960 megawatts (MW). Drax was the third power station in the area to be commissioned by the Central Electricity Generating Board (CEGB) following the discovery of the Selby Coalfield, the first being an expansion of Ferrybridge (2,000MW Ferrybridge ‘C’) and the second was a new 2,000MW station at Eggborough. The power station was built in two phases – the first phase comprised three units and began operation in 1973. The second phase of construction was completed in 1986, making Drax the last major coal-fired power station to be built in the UK.

Drax was initially conceived as the largest power station in the UK, at 3,000MW. The capacity was expanded further when the CEGB saw this as a good opportunity to install their first 660MW turbogenerator sets and the plans were revised to almost 4 gigawatts.

The turbine hall is around a quarter of a mile long (400m) and the chimney is the tallest industrial chimney in the UK at 259 metres high. The twelve natural draught cooling towers are 114 metres high and arranged in two groups of six to the north and south of the station.

Buildings and Plant Detail

Decarbonisation – Conversion to Biomass

Construction and Infrastructure

A conversion to biomass on such a large scale is a huge undertaking, and is in fact the largest decarbonisation project in Europe. One of the biggest challenges is the logistics behind sourcing the fuel. The biomass is acquired from sustainable forests in North America, where waste products are collected up and processed to create pellets suitable for feeding into the power station. The pellets are then transported by road and rail to Louisiana where they are transferred to 50,000 tonne barges to be brought to the UK. The final leg of the journey takes place by rail after which the wood pellets arrive at Drax and are housed in huge biomass storage domes. Unlike coal, which can be stored outside and open to the elements, biomass needs to be kept dry. The four purpose built domes can each hold 75,000 tonnes of biomass in a controlled atmosphere.

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Carbon Savings

The overall aim of converting to full-firing of biomass is to reduce the carbon emissions. Drax is the UK’s sole largest emitter of carbon, and although carbon is still released from burning wood chips, it is carbon that has recently been absorbed while the wood was growing in the forest. As the forest is replanted, further carbon is absorbed from the atmosphere to, in theory, create a carbon-neutral process. However, the sustainability of this process has been questioned. The biggest issue, opponents claim, is that the carbon released into the atmosphere will not be fully reabsorbed by new-growth trees. Transportation of the biomass across the Atlantic only further adds to the carbon emissions, along with the deforestation caused by many biomass projects. Drax claim their carbon emissions have been cut by 80%, but independent estimates indicate those emissions may have even increased as a result of the biomass conversion.

Future Plans

The move away from coal isn’t stopping at the conversion of four units to biomass. Drax aims to become free of coal by 2025 and has laid out plans to convert its remaining two coal-fired units to run on gas. The project will see the construction of two combined cycle gas turbine generators, the waste heat from which will be used to generate steam for two of the existing steam turbines. The gas turbines and two converted steam turbines will generate more electricity than the current total station output, while also lowering emissions.

Drax Image Gallery

Visit the plant detail pages above to view more images from each area of the power plant

During planning the CEGB decided Drax would be a good opportunity for the installation of their first 660MW turbogenerator sets. The station consists of 6 such sets, with a total generating capacity of almost 4 gigawatts.

The steam turbines, manufactured by CA Parsons are of the tandem-compound design comprising five cylinders – one high pressure, one intermediate pressure and three low pressure cylinders, with single reheat.

The huge turbine and generator sets are positioned at an angle within the turbine hall to reduce the width of the area the overhead cranes span.

A £100 million investment programme was undertaken by Siemens to replace the turbines between 2007 and 2012. The turbines consist of 28 separate turbine rotors which weigh more than 2,800 tonnes and have 80,000 individual turbine blades.

Drax Generating Units

List of power generating units at Drax Power Station:

Turbine Hall Pictures

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All six boilers were originally fired with bituminous coal. Between 2013 to 2016 three of the boilers were converted to fire biomass. One further unit was converted to fire biomass in 2018.

Boiler House and Mill Pictures

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Drax has an expansive fuel delivery and processing network. The part-conversion to biomass necessitated construction of additional storage facilities on site, along with a supply chain from North America.

Coal Handling and Storage

The original fuel processing and storage facilities at Drax is a relatively standard affair, similar to those at other large power stations in the UK. The coal was delivered via rail from the nearby collieries, mainly Kellingley, but since the closure of the UK’s last deep-level mine in 2016, coal is now imported from overseas. A merry-go-round system allows trains to be unloaded without stopping, before returning to collect more coal. Coal can be stored outside, open to the elements until it is ready to be used. Two bucketwheel excavators load coal from the stacks into the conveyor network to feed the power station.

Biomass Transportation and Handling

Biomass requires much more care when being handled and stored than coal. It must be kept dry at all times – the pellets would need to be scrapped if they became wet. In addition, the dust created while handling biomass can create an explosive atmosphere, so must be carefully controlled.

Biomass and Coal Handling Pictures

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